• Journal of the Korean Society for Heat Treatment
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• v.11 no.4
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• pp.305-314
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• 1998

This study has been performed to investigate into some effects of various amounts of $CO_2$ and CO gas added to the $50%NH_3-N_2$ based gas atmosphere on microstructure, hardness, chemical analysis and residual stress in the compound and diffusion layer of AISI H13 treated by gaseous nitrocarburising process. The compound layer formed in the surface is composed of mainly ${\varepsilon}-Fe_3$(N,C) and small amount of ${\gamma}^{\prime}-Fe_4N$ and cementite. The maximum hardness value obtainable from H13 steel is shown to be 1200 Hv and the effecvtive hardening depth increases with increasing CO content from 1% to 4%. In the case of CO content over 4%, however, it decreases with increasing CO content. The composition profiles of nitrogen and carbon are found to be within the ${\varepsilon}$-phase field located above the ${\varepsilon}+{\gamma}^{\prime}$ phase field in the Fe-N-C diagram. It is shown that the maximum value of compressive residual stress of H13 steel treated in atmospheres of $50%NH_3-(2,4)%CO_2-N_2-CO$ gas mixture is $48kg/mm^2$ and the depth to which residual stress is in Compressive state is $90{\mu}m$ for the atmosphere $50%NH_3-45%N_2-4%CO_2-1%CO$ gas mixture. It is consequently important to control the maximum value and size of compressive residual stress region in order to obtain desirable mechanical properties.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.226-234
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• 2010

Foliage residue toxicity experiment was performed against honeybee (Apis mellifera) with bifenthrin, a synthetic pyrethroid insecticide with strong acute contact toxicity and imidacloprid, a neo-nicotinoid insecticide with strong acute oral toxicity to know the honeybee toxicity at the residue level on the leaves of alfalfa and apple. Also, the formulation differences to honeybee toxicity were investigated with WP (2%) and EC (1%) of bifenthrin and WP (10%) and SL (4%) of imidacloprid. Generally, foliage residual toxicity of honeybee and residual amounts of tested insecticides was higher in alfalfa leaves with large leaf area per unit weight than in apple leaves. While on the other hand, the only bifenthrin WP treatment showed higher honeybee toxicity on apple leaves than alfalfa. Although imidacloprid showed higher residue amounts ranged $4.9{\sim}25.4\;mg{\cdot}kg^{-1}$ than bifenthrin ranged $0.6{\sim}12.7\;mg{\cdot}kg^{-1}$ on the leaves, the residual toxicity to honeybee was lower than bifenthrin because of its strong penetration character. In conclusion, the residual toxicity of insecticide to honeybee could be affected by the contact and vaporized toxicity of chemical, the residual amounts on the surface of leaves, and the leaf area per unit weight and formulation differences.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.677-688
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• 2006

Currently, the application of $TiO_2$ photocatalyst has been focused on purification and treatment of wastewater. However, the use of conventional $TiO_2$ slurry photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we studied that solar light/$TiO_2$ film system was designed and developed in order to examine disinfection characteristics of sewage wastewater treatment. The optimum conditions for disinfection such as solar light intensity, characteristic of sewage wastewater, amounts of $TiO_2$ and comparison of solar ligth/$TiO_2$ systems with UV light/$TiO_2$ system was examined. The results are as follows: (1) photocatalytic disinfection process with solar light in the presence of $TiO_2$ film more effectively killed total coliform (TC) than solar light or $TiO_2$ film absorption only. (2) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with remain resistant material. (3) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with the increase of amounts of $TiO_2$. (4) TC survival ratio decreased linearly with increasing UV light intensity. (5) The disinfection effect of solar light/$TiO_2$ slurry system decreased more than UV light/$TiO_2$ film systems. (6) The disinfection reaction followed first-order kinetics. We suggest that solar light instead of using artificial UV light was conducted to investigate the applicability of alternative energy source in the disinfection of TC and the degradation of organic material.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1168-1174
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• 2017

Objective: The aim of the study was to evaluate the effects of different nitrate levels (150, 300, 450, and 600 ppm $KNO_3$) on the volatile compounds and some other properties of pastırma. Methods: Pastırma samples were produced under the controlled condition and analyses of volatile compounds, and thiobarbituric acid reactive substances (TBARS) as an indicator of lipid oxidation, non-protein nitrogenous matter content as an indicator of proteolysis, color and residual nitrite were carried out on the final product. The profile of volatile compounds of pastırma samples was analyzed by gas chromatography/mass spectrometry using a solid phase microextraction. Results: Nitrate level had a significant effect on pH value (p<0.05) and a very significant effect on TBARS value (p<0.01). No significant differences were determined in terms of $a_w$ value, non-protein nitrogenous substance content, color and residual nitrite between pastırma groups produced by using different nitrate levels. Nitrate level had a significant (p<0.05) or a very significant (p<0.01) effect on some volatile compounds. It was determined that the amounts and counts of volatile compounds were lower in the 450 and especially 600 ppm nitrate levels than 150 and 300 ppm nitrate levels (p<0.05). While the use of 600 ppm nitrate did not cause an increase in residual nitrite levels, the use of 150 ppm nitrate did not negatively affect the color of pastırma. However, the levels of volatile compounds decreased with an increasing level of nitrate. Conclusion: The use of 600 ppm nitrate is not a risk in terms of residual nitrite in pastırma produced under controlled condition, however, this level is not suitable due to decrease in the amount of volatile compounds.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.4
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• pp.35-44
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• 2008

A self-centering energy-dissipative(SCED) bracing system has recently been developed as a new seismic force resistant bracing system. The advantage of the SCED brace system is that, unlike other comparable advanced bracing systems that dissipate energy such as the buckling restrained brace(BRB) system, it has a self-centering capability that reduces or eliminates residual building deformations after major seismic events. In order to investigate the effects of torsion on the SCED brace and BRB systems, nonlinear time history analyses were used to compare the responses of 3D model structures with three different amounts of frame eccentricity. The results of the analysis showed that the interstory drifts of SCED braced frames are more uniform than those of BRB frames, without regard to irregularity. The residual drift and residual rotation responses tended to decrease as irregularity increased. For medium-rise structures, the drift concentration factors(DCFs) for SCED systems were lower than those for BRB frames. This means that SCED-braced frames deform in a more uniform manner with respect to building height. The effect of the torsional irregularity on the magnitude of the DCFs was small.

• Journal of Soil and Groundwater Environment
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• v.23 no.2
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• pp.23-29
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• 2018

This study explored secondary effects of the residual hydrofluoric acid (HF) after a hypothetical acid spill accident by investigating the long-term dissolution of minerals and leaching of pre-existing arsenic (As) from two soil samples (i.e., KBS and KBM) through batch and column experiments. An increase in the HF concentration in both soil samples resulted in a dramatic increase in the release of major cations, especially Si. However, the amounts of mineral dissolved were dependent on the soil type and mineral characteristics. Compared to the KBM soil, relatively more Ca, Mg and Si were dissolved from the KBS soil. The column experiment showed that the long-term dissolution rates of the minerals are closely associated with the acid buffering capacity of the two soils. The KBM soil had relatively higher effluent pH values compared to the KBS soil. Also, more As was leached from the KBM soil, with a more amorphous hydrous oxide-bound As fraction. These results suggest that the potential of heavy metal leaching by the residual acid after an acid spill will be influenced by heavy metal speciation and mineral structure in the affected soil.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.246-253
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• 2011

This experiment was carried out to examine the residual amount variation of carbendazim and chlorpyrifos in fruit parts of red pepper according to the open field and/or the rain shelter house. It was shown higher residual amounts of agrochemicals in the field than the house condition at two hours (0 day) after chemical application, but it was shown higher residual amounts in the house at 5 days and 10 days. Although the residual amount in the field was higher than in the house at the beginning, the chemicals fast degraded in field condition. Carbendazim and chlorpyrifos remained as time passed in order of receptacle, but the residual amounts of two chemicals in leaf at $5^{th}$ day. Carbendazim and chlorpyrifos were lessened until 10 days after chemical application, and reduction rate were 19.1% and 66.4% in flesh, 45.2% and 62.3% in receptacle, and 41.6% and 72.0% in the stalk, respectively. The reduction rate at 15 days showed 31.1%, 75.3% in flesh, 43.5%, 81.7% in receptacle, and 47.7%, 82.8% in stalk, respectively. Therefore the reduction rate of carbendazim showed receptacle > stalk > flesh, and that of chlorpyrifos showed stalk > receptacle > flesh in order. The calculated half-life of carbendazim showed 29.6 days in flesh, 13.6 days in receptacle, and 16.0 days in stalk, but that of chlorpyrifos showed 8.3 days in flesh, 8.3 days in receptacle, and 6.3 days in stalk. In conclusion, the half-life of carbendazim was longer than that of chlorpyrifos in even part, and especially was longest in flesh part of fruit.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.3 s.116
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• pp.72-78
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• 2006

The extraction properties of the biological waste originated from the Tobacco industry were evaluated. The biological waste have been recycled and transformed into a valuable material, so called a reconstituted tobacco sheet(Recon) by the papermaking process. In this process, The mechanical extraction process, which divides the mixed raw material slurry into the soluble stock and the insoluble stock, could affect not only the quality of final Recon product but also the productivity of whole Recon making process. This study investigated the effects of the extraction process on the slurry properties in detail. In order to quantify the amounts of the solubles which resided in the insoluble fibers, the washing treatment of the stock before and after squeezing process was applied. The amounts of the residual solubles showed little changes according to each stage of the extraction process. The fractionation of the slurry showed the difference in the amount of soluble in the stock depending on the size of the biological waste. After the extraction process, the bigger size fiber portion contained about 19%(by weight) in soluble after pressing but the smaller size fiber portion 9% in soluble. The fractionation ratio of the stocks also was changed by the screw press process, which could demonstrate the physical effects of the mechanical extraction.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.346-351
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• 1995

To produce ethanol from Jerusalem artichoke powder efficiently, Kluyveromyces marxianus F043 cells were encapsulated in 2% sodium alginate and were cultured in a countinuous reactor to investigate the fermentation properties. Immobilized K. marxianus F043 cells were activated for 48 hours in a fermentor for continuous ethanol production. The culture in a CSTR using a Jerusalem artichoke substrate treated with 2% cellulase showed a decrease in ethanol concentration and an increase in residual saccharide concentration with a increasing dilution rate. Optimum conditions for high ethanol productivity and low residual saccharide output were clarified to be given at a dilution rate of 0.2 h$^{-1}$ and a Jerusalem artichoke medium concentration of 75 g/l. Ethanol productivity of 3.1 g/l-h and saccharide utilization of 62.6% were obtained under the optimum condition. When the fermentation was performed for 3 weeks under these conditions, the effluent medium showed stable ethanol concentrations of 16.3 - 17.9 g/l and viable cells of 6.60-7.16 log cells/ml without contamination. Trace amounts of methyl, n-propyl, iso-butyl, isoamyl alcohols besides ethanol were detected.